Compiler panics on out-of-bounds array accesses

[jfecher]

Description

Aim

Attempted to write an invalid noir program:

fn main(y: [u32; 5]) {  
    constrain y[6] == 2;
}

Expected behavior

Compiler will issue an error explaining that an out-of-bounds array access has occurred with the original source location of the error, the index value, and the array length.

Bug

Compiler hits an unreachable expression and panics:

thread 'main' panicked at 'index out of bounds: the len is 5 but the index is 6', crates/noirc_evaluator/src/ssa/anchor.rs:137:13
stack backtrace:
   0: rust_begin_unwind
   [...]

To reproduce

1. Run the example code above with nargo prove p

Additional context

The current panic message is fine, but being issued from a panic is confusing to users since calls to unreachable are usually indicative of a compiler crash rather than an intended error reporting. We should thread Location data down to these Load/Store instructions in SSA so that we can issue an error in the same format as other compiler errors.